Riveting tool



' y 1939- P. VAN SITTERT El AL 2,164,970

RIVETING TOOL Filed Sept. 10, 1957 |NV NTORS ATTORNEY Patented July 4, 1939 UNITED STATES PATENT OFFICE RIVE-TING TOOL Paul Van Sittert, Cleveland Heights, and John H.

Engeln, Cleveland, Ohio, assignors to The Cleveland Pneumatic Tool Company,

Cleveland,

11 Claims.

This invention relates broadly to fluid actuated riveting tools generally known and referred to as riveting hammers, but more particularly to riveting tools especially adapted for setting relatively small rivets made of comparatively soft metal such as aluminum or aluminum alloys, as generally used in the manufacture of airplane wings and the like.

When aluminum plates are riveted together, it

is very important to upset the rivet without allowing the rivet set to come in contact with the plates and damage the same by impressing an annular groove thereon around the rivet head. In practice, it has been found that when the riveting operation is performed with the usual riveting hammer, wherein the hammer is adapted to deliver a rapid succession of impacts to the rivet set, it is very difficult for the operator to control the number of impacts deliveredto the rivet set,

20, with the result that some of the rivets were not set completely while others were set beyond the proper shape with the plates damaged by the rivet set.

It is therefor one object of this invention to 25 produce a riveting hammer capable of delivering a single impact to the rivet set for each opening of the motive fluid controlling valve.

Another object of this invention is to produce a riveting hamer forming a relatively light and 3d compact assembly which is strong, durable, ellicient and comparatively inexpensive to manufacture.

Other objects and advantages more or less ancillary to the foregoing reside in the specific con- 35 struction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specification.

In the drawing:

Fig. 1 is a side elevational sectional view of the tool showing a portion of the handle.

Fig. 2 is a fragmentary view of the tool shown in Fig. l, with the valve and the hammer in a different position.

Fig. 3 is a cross sectional view taken through a plane indicated byline 33 in Fig. 2.

Fig; 4 is a cross sectional view taken through a line 4-4 in Fig. 1.

Referring to the drawing in which like symbols 50; designate corresponding parts throughout the several views, l0 represents the outer cylinder of the tool which has an enlarged upper end H externally threaded to receive the usual handle l2. This upper end of the outer cylinder I0 is 55; also provided with a counterbore. l3 accommodating, in the bottom thereof, the head l4 of an inner cylinder l5 which extends into the outer cylinder to a place near the lower end thereof where it is fitted against lateral relative movement as at [6. These two cylinders are mounted .5 with an annular space H therebetween communicating with the lower interior of the inner cylinder through radial ports l8. Axially through the lower end of the outer cylinder It, there is a bore 19 having slidable therein the shank 20 of a 1 0, rivet set 2|, which shank projects into the lower end of the inner cylinder to receive the impacts of a hammer 22 which is reciprocably mounted within the inner cylinder.

Within the counterbore l3 above the head I4, I}, there is a plate 23 having a central bore 24 of a diameter somewhat larger than the inner diameter of the cylinder l5, and a valve block 25 which protrudes from the upper end of the cylinder Ill into a counterbore 26 formed within the handle so l2. On top of this valve block, there is a plate 2'? engaging an annular land 28 formed on the bottom of the counterbore 26. The head l4, plate 23, valve block 25 and plate 21, are clamped between the outer cylinder 59 and the handle I2, 5 and are preferably locked against relative rotation by a dowel pin 29 extending therethrough.

Centrally disposed through the valve block 25, there is a bore 30 having a spool valve 3| slidable therein. This valve has its stroke in one 30 direction checked by the upper plate 21, and in the other direction by the lower plate 23. This valve is formed with two counterbores 32 and 33 opening from each each thereof and having a partition 34 therebetween transpierced by a small 35 port 35. Equally spaced within the valve block bore 39, there are four annular grooves 36, 31, 38 and 39, while the valve ti is formed with two external annular grooves 40 and 4!. Disposed within the valve block 25, there are inlet ports 42 4 leading into'the groove 38 and extending through the upper plate 2'5 into a circular chamber 43 having motive fluid supplied thereto through a port 44. Leading from the groove 3'! to the annular space ll between the cylinders it and I5, 45 there is a port 45, while the groove 38 is connected through ports 45 to an annular groove 41 formed between the valve block 25 and the handle l2, which annular groove is connected to the atmosphere through an exhaust port 48, and the groove 39 is connected with the interior upper end of the inner cylinder i 5 through a port 49.

Located within the counterbore 33 of the valve 3|, there is a compression spring 53 having one end resting on the partition 34 while the other 53' end engages the upper plate 21, which plate is also provided with a radially extending channel leading from the upper end of the valve block bore 30 into the annular space 41.

In the operation of the tool, let it be assumed that motive fluid from a source of supply is admitted to the handle I2 to be controlled by a throttle valve (not shown) for admission into the inlet port 44 as long as the throttle valve is held open. If the parts are positioned as shown in Fig. 1, the motive fluid will flow into the groove 36 via the chamber 43 and ports 42. Passing by the valve groove 40, the motive fluid flows into the valve block groove 31 from where it will be admitted into the front end of the inner cylinder I5 via the ports 45, the annular space I'I between the two cylinders, and the radial ports I8, which ports are located to allow the admission of the motive fluid to the front end of the hammer 22 for driving the same upwardly. During the upward or return stroke of the hammer, the atmosphere and the motive fluid previously admitted into the inner cylinder back of the hammer 22, is free to exhaust therefrom via the port 49, the annular groove 39, the valve groove 4|, the annular groove 38, the ports 46, the annular groove 41 and finally the exhaust port 48. When the hammer 22 reaches the end of its return stroke, it will cover the port 45, and thereafter compress the atmospheric air and motive fluid remaining in the upper end of the cylinder I5 and in the valve counterbore 32, thereby causing this compressed fluid to act on the valve partition 34 for compressing the spring 50 and shifting the valve into the position shown in Fig. 2. During the shifting of the valve 3|, the atmospheric air within the valve counterbore 33 is free to exhaust therefrom through the radial channel 5|.

With the valve 3| positioned as shown in Fig. 2, the groove 36, now uncovered by the valve, will allow the admission of the motive fluid into the cylinder I5 back of the hammer 22 for effecting the working stroke of the hammer. In this instance, the valve is maintained in open position relative to the groove 36, due to the action of the motive fluid on the front end of the valve and on the corresponding side wall of the partition 34. During the downward movement of the hammer, the motive fluid previously admitted into the front end of the cylinder I5 is free to exhaust therefrom via the ports I8, the annular space H, ports 45, grooves 31, 42 and 38, ports 46, the annular space 41 and finally the exhaust port 48. When the hammer 22 reaches the end of its working stroke, it will engage the shank 20 of the rivet set 2| for delivering a blow thereto causing the setting of the rivet engaged by the rivet set.

If the throttle valve controlling the admission of the motive fluid to the port 44 is left open after the hammer has delivered its blow to the rivet set, the valve 3| will remain into the position shown in Fig. 2, with the motive fluid admitted into the cylinder I5 back of the hammer 22 from where it is prevented to exhaust through the port 49, because this port is still closed by the valve 3|. It will now be understood that even though the throttle valve is kept open, the hammer will remain stationary within the front end of the cylinder I5. In this instance, any amount of motive fluid which may escape from the back to the front end of the hammer, is free to exhaust therefrom through the ports I8, which ports communicate with the main exhaust port 48, thereby preventing pressure to be built up into the front end of the cylinder which might possibly cause a partial return stroke of the hammer.

To again cause the return stroke of the hammer, it is first necessary for the operator to release the trigger of the throttle or simply close the throttle and thereby cut off the admission of the motive fluid to the rear end of the inner cylinder I5. In this instance the motive fluid previously admitted therein and holding the valve 3| in the position shown in Fig. 2, will gradually escape through the small valve port 35, the radial groove 5|, the annular space 41 and the exhaust port 48, thereby relieving the motive fluid pressure acting on the front end of the valve, and allowing the valve to be shifted by the spring 50 into the position shown in Fig. 1. This shifting of the valve 3| by the spring 50 will take place almost immediately after the throttle valve has been closed by the operator, because the force of the spring is calculated to be only slightly less than the force exerted on the opposite side of the valve by the motive fluid admitted through the groove 36 and partly exhausting through the restricted port 35.

With the valve 3| again positioned as shown in Fig, l, the operator may open the throttle valve for again admitting motive fluid into the front end of the inner cylinder I5 for effecting the return stroke of the hammer preparatory to its working stroke in the manner above described.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modifications of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

We claim:

1. In a tool of the character described, a cylinder having a fluid actuated hammer reciprocable therein, a valve casing having motive fluid admittable therein, a valve within said casing alternatively controlling the admission of the motive fluid into both ends of said cylinder for actuating said hammer, means on said valve having motive fluid admitted thereon for maintaining said valve in open position relative to one end of said cylinder as long as motive fluid is admitted into said casing, and other means for automatically shifting the valve into open position relative to the other end of said cylinder immediately after the admission of the motive fluid into said casing has been cut off.

2. In a tool of the character described, a cylinder having a fluid actuated hammer reciprocable therein, a valve casing having motive fluid admittable therein, a valve within said casing alternatively controlling the admission of the motive fluid into both ends of said cylinder for actuating said hammer, actuating areas on one side of said valve having motive uid admittable thereon from said casing for maintaining said valve in open position relative to one end of said cylinder as long as motive fluid is admitted into said casing, and spring means acting on the other end of said valve for shifting the valve into open position relative to the other end of said cylinder immediately after the admission of the motive fluid into said casing has been cut off.

3. In a tool of the character described, a cylinder having a fluid actuated hammer reciprocable therein, a valve casing having motive fluid admittable therein, a valve within said casing controlling the admission of the motive fluid into both ends of said cylinder for effecting the working and return strokes of said hammer, spring means acting on said valve for shifting and maintaining it in hammer return stroke position, and actuating areas for said valve subjected to fluid compressed within said cylinder by said hammer near the end of its return stroke for shifting said valve into hammer working stroke position, said areas being subsequently subjected to motive fluid from said casing for maintaining said valve in said last mentioned position to prevent the return stroke of the hammer as long as motive fluid is admitted into said casing. 1

4. In a tool of the character described, a cylinder having a fluid actuated hammer reciprocable therein, a valve casing having motive fluid admitted therein, a valve within said casing controlling the admission of the motive fluid into said cylinder for eflecting the working and return strokes of said hammer, means associated with said valve for mechanically shifting and momentarily maintaining it in hammer return stroke position, and means on said valve subjected to fluid pressure for shifting the valve into hammer working stroke position and maintaining it in this last position as long as motive fluid is admitted intosaid casing.

5. In a tool of the character described, a cylinder having a fluid actuated hammer reciprocable therein, a valve having motive fluid ad' mitted thereto, said valve being automatically movable in two directions for controlling the admission of the motive fluid into said cylinder for effecting the working and return strokes of said hammer, spring means acting on said valve for shifting and momentarily maintaining it in hammer return stroke position, and means on said valve subjected to fluid pressure for shifting the valve into hammer working stroke position and maintaining it in this last position as long as motive fluid is admitted to the valve.

6. In a single blow riveting hammer, a cylinder having a fluid actuated hammer member reciprocable therein, a valve having motive fluid admitted thereto, said valve being automatically movable in two directions for controlling the admission of the motive fluid into said cylinder for effecting the working and return strokes of said hammer member, resilient means acting on said valve for shifting and momentarily holding it in one position effecting one stroke of the hammer member, and means on said valve subjected to fluid pressure for shifting the valve into another position effecting the other stroke of the hammer member and for automatically holding the valve in this last position as long as motive fluid is admitted to the valve, thereby admitting motive fluid into the cylinder for holding the hammer member against further reciprocation.

'7. In a riveting tool of the single impact type, a cylinder, a fluid actuated hammer reciprocable within said cylinder, passages opening into said cylinder having motive fluid admitted therein, an automatically actuated passage controlling means affording timely distribution of the motive fluid into said cylinder through said passages in a manner effecting a return and a working stroke of said hammer, and means automatically maintaining said passage controlling means in a predetermined position causing subsequent admission of the motive fluid into, said cylinder to hold said hammer at the end of its working stroke as long as motive fluid is supp-lied to at least one of said passages.

8. In a riveting tool of the single impact type, a cylinder, a. fluid actuated hammer reciprocable within said cylinder, motive fluid conveying passages opening intosaid cylinder, and an automatically actuated passage controlling valve affording admission of the motive fluid into said cylinder through said passages in a manner effecting a single return and a single working stroke of said hammer.

9. In a riveting tool of the single impact type, a cylinder, a fluid actuated hammer reciprocable within said cylinder, motive fluid conveying passages opening into said cylinder, a throttle-valve controlling the supply of the motive fluid to said passages, and automatically actuated passage controlling means afiording admission of the motive fluid into said cylinder through said passages in a manner effecting a single working stroke of said hammer for each opening of said throttle valve.

10. In a riveting tool of the single impact type,

a cylinder having a tool implement carried thereby, a fluid actuated hammer reciprocable within said cylinder, motive fluid conveying passages opening into said cylinder, a throttle-valve controlling the supply of the motive fluid to said passages, and automatically actuated passage controlling means affording admission of the motive flui-d into said cylinder through said passages in a manner effecting the reciprocation of said hammer and a single impact delivered thereby to said tool implement for each opening of said throttle valve.

11. In a tool of the character described, a cylinder, a fluid actuated hammer reciprocable within said cylinder capable of return and working strokes therein, a valve casing having motive fluid admitted therein, passages admitting motive fluid from said casing alternatively into the end portions of said cylinder for actuating said hammer, an automatically actuated valve within said casing controlling said passages for producing said alternative admission, and means on said valve automatically subjected to fluid pressure after each working stroke of said hammer for holding said valve in a position causing an uninterrupted admission of the motive fluid into one end portion of said cylinder as long as motive fluid is admitted into said casing.

PAUL VAN SITTERT. JOHN H. ENGELN. 

